1. Field of the Invention
The present invention relates to a vessel tracking device, which is introducible into a vessel of a human body.
2. Description of the Prior Art
When an elongate unit, such as for example a pacemaker lead, is going to be introduced into a vessel of the human body for temporary or permanent placement it is often preferable to use an aid for guiding the unit. A vessel tracking device is used for tracking vessels until a front end, or distal end, of the device reaches a predetermined destination. Then the very elongate unit can be introduced guided by the vessel tracking device. When introducing the device, typically, tricky passages are reached where it is difficult to go ahead. In order to facilitate such passages, a distal end portion being one or a few centimeters long, is often prebent. On the other hand such a prebend can cause problems when a vessel is narrowing.
U.S. Pat. No. 5,728,148 discloses a stylet unit where the bend of the distal end portion is variable by remote control thereof. The stylet unit has coaxially arranged stylet elements, consisting of a tubular stylet sleeve and an internal stylet, which is movable back and forth within the sleeve. A distal end portion of the stylet is prebent to a great extent, while the sleeve is straight. When, during the introduction of the stylet unit into a vessel, a straight distal end portion is desirable, the stylet is retracted into the sleeve, and when a bend is desirable the stylet is pushed out of the sleeve. This prior art vessel tracking device is unnecessary difficult to manoeuvre, since when moving the stylet along the sleeve the distal end thereof is moved in relation to the vessel. Thus the stylet movement has to be compensated for by counter movement of the sleeve.